| Lantiq SoC External Bus memory mapped GPIO controller |
| |
| By attaching hardware latches to the EBU it is possible to create output |
| only gpios. This driver configures a special memory address, which when |
| written to outputs 16 bit to the latches. |
| |
| The node describing the memory mapped GPIOs needs to be a child of the node |
| describing the "lantiq,localbus". |
| |
| Required properties: |
| - compatible : Should be "lantiq,gpio-mm-lantiq" |
| - reg : Address and length of the register set for the device |
| - #gpio-cells : Should be two. The first cell is the pin number and |
| the second cell is used to specify optional parameters (currently |
| unused). |
| - gpio-controller : Marks the device node as a gpio controller. |
| |
| Optional properties: |
| - lantiq,shadow : The default value that we shall assume as already set on the |
| shift register cascade. |
| |
| Example: |
| |
| localbus@0 { |
| #address-cells = <2>; |
| #size-cells = <1>; |
| ranges = <0 0 0x0 0x3ffffff /* addrsel0 */ |
| 1 0 0x4000000 0x4000010>; /* addsel1 */ |
| compatible = "lantiq,localbus", "simple-bus"; |
| |
| gpio_mm0: gpio@4000000 { |
| compatible = "lantiq,gpio-mm"; |
| reg = <1 0x0 0x10>; |
| gpio-controller; |
| #gpio-cells = <2>; |
| lantiq,shadow = <0x77f> |
| }; |
| } |
